In a bonded neodymium-iron-boron (NdFeB) magnet, neodymium oxide (Nd.sub.2 O.sub.3) is present. Nd.sub.2 O.sub.3 reacts with water (H.sub.2 O) to form neodymium hydroxide (Nd(OH).sub.3) according to: EQU Nd.sub.2 O.sub.3 +3H.sub.2 O.fwdarw.2Nd(OH).sub.3
The density of Nd.sub.2 O.sub.3 is 7.28 g/cc, whereas the density of Nd(OH).sub.3 is 5.60 g/cc. This decrease in density resulting from the formation of Nd(OH).sub.3 causes a volumetric expansion, which may cause an eruption in the magnet. A motor made of such magnets and having a sufficiently small air gap between moving components can be stalled by such eruption. A need exists to prevent formation of Nd(OH).sub.3 in bonded NdFeB magnets, which are used in a wide spectrum of industries including computers, automobiles, consumer electronics, and household goods.